The molding of composite materials using BMC and SMC contributes greatly to mass production technology. However, the products made by this molding process have some problems. For example, in the case of a product with rib part, a hollow occasionally appears at the opposite surface of the rib. Furthermore, the strength of rib is reduced at the resin rich corner of rib. In order to solve these problems, it is necessary to investigate the flow state of BMC during the molding process by experimental and numerical analyses.
In this paper, the dependence of flow state of BMC on the length of fiber involved was investigated. The experiments were carried out at room temperature so as to avoid the effect of polymerization. In the numerical analysis, a model consisting of isotropic laminae between each prepressed BMC laminates was used to simulate slippage in the specimen.
The experimental and analytical results showed that the resin rich part at the corner of rib became larger as the fibers in BMC became shorter. The higher the height of rib, the larger the distortion of flow pattern and the variation of the strength of this part.
